Fix Harmony sets and maps to allow undefined as keys.

test/mjsunit/harmony/collections.js

Index: test/mjsunit/harmony/collections.js
diff --git a/test/mjsunit/harmony/collections.js b/test/mjsunit/harmony/collections.js
index d3c6c0f258030474dc717b27997c74c064630870..7e024ebfe86e6639b4d86ecd94e69904848ab087 100644
--- a/test/mjsunit/harmony/collections.js
+++ b/test/mjsunit/harmony/collections.js
@@ -101,7 +101,7 @@ function TestMapBehavior2(m) {
     TestMapping(m, i / 10, new Object);
     TestMapping(m, 'key-' + i, new Object);
   }
-  var keys = [ +0, -0, +Infinity, -Infinity, true, false, null ];
+  var keys = [ +0, -0, +Infinity, -Infinity, true, false, null, undefined ];
   for (var i = 0; i < keys.length; i++) {
     TestMapping(m, keys[i], new Object);
   }